The pFN6 and pFC7 (HQ) Flexi® Vectors are used for inducible expression of HQ-tagged fusion proteins in E. coli and cell-free systems using the T7 RNA polymerase promoter. The HQ tag and polyhistidine tag (His) are comparable in their affinity for Ni ions and will bind to all His-binding surfaces and resins. In certain cases the HQ-tagged proteins can be eluted from the affinity columns at lower concentrations of imidazole—a property useful for some downstream applications such as enzymatic reactions. As with His tag, proteins can be expressed from bacterial, insect and mammalian systems and purified under either native or denaturing conditions.
Use these Flexi® vectors for bacterial and cell-free protein expression of ORFs and purify the tagged proteins with Ni (His-affinity) resin for standard protein purification and prokaryotic expression applications. The pFN6A/K (HQ) Flexi® Vectors (Cat.# C8511, C8521) are designed for protein expression with an N-terminal HQ tag. The pFC7A/K (HQ) Flexi® Vectors (Cat.# C8531, C8541) are designed for protein expression with an C-terminal HQ tag.
About the Flexi® Vector System
The Flexi® Vector System is a simple, yet powerful, directional cloning method for protein-coding sequences. It is based on two rare-cutting restriction enzymes, SgfI and PmeI, and provides a rapid, efficient and high-fidelity way to transfer protein-coding regions between a variety of Flexi® Vectors without the need to resequence. Directly use recombinant clones and minimize time wasted screening background colonies. The versatile cloning of the Flexi® system means you can choose from a variety of expression systems and fusion tag orientations and then transfer to others as required. Direct transfers can only occur between two N-terminal tagged vectors or from an N-terminal to a C-terminal vector.
Note: Flexi® Vectors contain the lethal barnase gene to reduce background colonies without inserts during the subcloning procedure. Using the Flexi® Vector Cloning System replaces the barnase gene with your insert. These vectors, as purchased, cannot be cultured in normal laboratory strains of E. coli without an insert.